如何使用Console.WriteLine打印变量

Question

The following code demonstrates the use of the sleep() method for making a thread pause for a specific period of time.

When I run this code :-

class Program
{
    class ThreadCreationProgram
    {
        public static void CallToChildThread()
        {
            Console.WriteLine("Child thread starts");

            // the thread is paused for 5000 milliseconds
            int sleepfor = 5000;

            Console.WriteLine("Child Thread Paused for {0} seconds");
            Thread.Sleep(sleepfor);
            Console.WriteLine("Child thread resumes");
        }

        static void Main(string[] args)
        {
            ThreadStart childref = new ThreadStart(CallToChildThread);
            Console.WriteLine("In Main: Creating the Child thread");
            Thread childThread = new Thread(childref);
            childThread.Start();
            Console.ReadKey();
        }
    }
}

I get this output-

In Main: Creating the child thread
Child thread starts
Child thread paused for <0> seconds
Child thread resumes

But what i expect is :-

In Main: Creating the child thread
Child thread starts
Child thread paused for <5> seconds
Child thread resumes

How can I do it any suggestions?

Answer 1

I think this is where you mistake is:

Console.WriteLine("Child Thread Paused for {0} seconds", (sleepfor/1000).ToString());

You didn't specify where the value for the {0} comes from.

Also you need to calculate from milliseconds to seconds, thats why /1000

Answer 2

If you want to see Child thread passed for <5> seconds , then you need to print exactly that.

Below is the problem line of your code

Console.WriteLine("Child Thread Paused for {0} seconds");

This should be

Console.WriteLine("Child Thread Paused for <{0}> seconds", sleepfor/1000);

As you notice, you haven't specified the parameter {0} in your call. You can refer to the documentation on Console.WriteLine()

Note that Console.WriteLine follows the formatting rules set by String.Format . The format string rules can be seen here .

In the newer syntax you don't need to use the place holders like {0} but can embed the expression itself in the string, called Interpolated Strings

Console.WriteLine($"Child Thread Paused for <{sleepfor/1000}> seconds");

Answer 3

Console.WriteLine("Child Thread Paused for <{0}> seconds", sleepfor/1000);

或C＃6方法：

Console.WriteLine($"Child Thread Paused for <{sleepfor/1000}> seconds");